<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>

  
</body>
<script>
  function render(){
  
    let sum=0
    let cha
    let ji=1
    let shang
   let a=+prompt('请输入第一数字')
   let b=+prompt('请输入第二数字')
   let c=+prompt('请输入第三数字')
  sum=a+b+c
  cha=a-b-c
  ji=a*b*c
  shang=a/b/c
  return  alert(`和为 ${sum} 差为${cha} 积为${ji} 商为${shang}`)
  }
 
  console.log(render());
</script>
</html>